Agents seized documents from Cohen's office relating to a number of topics, including a payment he made to Stormy Daniels, an adult film actor, to keep quiet about an affair she said she had with Trump starting in 2006, The New York Times reported.
Cohen called the raid "completely inappropriate and unnecessary."
"Today the U.S. Attorney's Office for the Southern District of New York executed a series of search warrants and seized the privileged communications between my client, Michael Cohen, and his clients," Cohen's lawyer, Stephen Ryan, said. "I have been advised by federal prosecutors that the New York action is, in part, a referral by the office of special counsel, Robert Mueller."
The Times reported the search doesn't appear to be directly linked to Mueller's investigation into whether Russia interfered in the 2016 U.S. presidential election or whether the Trump campaign colluded with Russia.
A unnamed source briefed on the raid told the Times the FBI also seized tax documents and business records.
Trump has denied allegations he had an affair with Daniels and said he was unaware Cohen arranged the $130,000 payment.
Trump said the raid was "a disgraceful situation."
"I have this witch hunt constantly going on," he told reporters. "It's an attack on our country ... what we all stand for."
Trump went on to describe the special counsel "the most conflicted group of people I have ever seen."